Durable Materials The weight bags adopt premium 600D fabric covering with PVC, double-stitched seam, guarantee tear resistance and durability, long service life for years. Tighter VelcroThe length of the Velcro is increased to 14cm, which is more than the usual 9cm length in the market, which can adjust the size of the roof bars more tightly. Load Capacity Each sandbag can hold up to about 25 pounds on sand, rock or dirt and other surfaces, so there's nothing to worry about for the tent that is blown away by the wind or other elements. Set of 4 weight bagsStabilize any instant canopy, each sand weight bag size is 16"X14", suitable for pop up canopy structures or folding gazebos, furniture patio, with a set of weight bags durable universals. Sand NOT IncludedYou can fill it with sand, rocks or sealed water bottle or water bag, please note sand is NOT included, bags ONLY.